The cloud-storage arms race heated up even more on Monday when Microsoft gave its OneDrive for Business service a big capacity boost.

The per-user storage provided by OneDrive for Business is rising from 25 gigabytes to 1 terabyte. That applies to both the standalone version of the product and the versions that come bundled with Office 365.

The standalone version of OneDrive for Business is available as a $5-per-month option with the free Office Online Web-based productivity suite. Microsoft is currently offering the first year's subscription at half the price. That promotional offer is available through September.

Microsoft also announced that for the first time, it is including OneDrive for Business with Office 365 ProPlus, a full-featured version of the desktop Office suite that is sold via an annual subscription for $12 per user, per month. These subscribers will also get 1 terabyte of storage per user.

OneDrive for Business, previously called SkyDrive Pro, is a service where employees can store, share and sync personal work files.

OneDrive for Business is included with most editions of Office 365, the cloud email and collaboration suite that includes online versions of Exchange, Lync and SharePoint, and with the standalone SharePoint Online service.

These Office 365 editions vary in price depending on their features and components. For example, Office 365 Small Business costs $5 per user, per month, while Office 365 Enterprise E4 goes for $22 per user, per month, to mention just two of the bundles.

The enterprise file sync and share market is crowded with specialty vendors such as Box, Dropbox, Accellion, Watchdox and Egnyte, and with products from larger providers such as Google, IBM, Citrix and EMC.

This type of storage product has become an essential component of modern collaboration systems designed to allow colleagues to jointly edit documents and access files from a variety of devices, including smartphones, tablets and PCs, via different methods including native mobile apps and standard Web browsers.

Dropbox charges $15 per user, per month for an unlimited amount of storage as part of its Business plan.

Meanwhile, Box charges $15 per user, per month for 1 terabyte of storage in its Business plan, and $35 per user, per month for unlimited storage.

Google Apps for Business, which costs $5 per user, per month, includes 30 gigabytes of Gmail and Drive storage. Customers can purchase more storage in various increments, including 1 terabyte for $89 per user, per month.

As part of its free Google account for individual consumers, Google offers each person 15 gigabytes of standard storage for Gmail, Drive and Google+ Photos, 100 gigabytes for $1.99 per month and 1 terabyte for $9.99 per month. Google chopped down those prices from $4.99 and $49.99, respectively, in March.